Netflix, Inc. (NASDAQ:NFLX) is by far my largest holding. Not because it's the one I invested the most in -- far from it. I only invested 1.5% of my original invested funds in Netflix. It has since grown to an astounding 20% of my portfolio thanks to 3,000% gains. Some might argue that is too much to have riding on a single company and would've sold off some of the position to lock-in those gains.

Not me. Even after the massive run the stock has gone on, I see a business with several big growth opportunities that can meaningfully move the needle. 

Netflix logo and program images shown on TV and other electronic devices.

Netflix available across all your devices. Image source: Netflix, Inc.

Netflix was my first investment back in 2007, just as the company was introducing its online streaming. I was one of the disillusioned customers of Blockbuster -- now owned by DISH -- that found Netflix a couple of years earlier, when I was charged $40 in late fees for a movie that I could have purchased for $20. I cut up my Blockbuster card, joined Netflix and never looked back. I saw then what I see now: a company that is providing an unbeatable service at a reasonable price. I love the programming, my personal dealings with its customer service have been seamless, and these experiences as a consumer (plus some big business levers) have made me a more confident investor.

Ready to take on the world

In addition to providing a great customer experience, Netflix has a large un-tapped pool of potential customers. Its total addressable market based on fixed-line broadband subscribers would be an estimated 766 million homes worldwide.  Other estimates see that number growing to 925 million by 2020. Even excluding an estimated 300 million potential customers in China, a country Netflix itself admits would be difficult to enter, the company's addressable market could exceed 625 million potential customers within three years.

Netflix home page displaying images from Marvel's Daredevil, a Netflix original.

Netflix available in 200 countries -and in Portuguese! Image source: Netflix, Inc.

Within its US market, the number of households is estimated at 125 million, of which Netflix counts 49 million subscribers, for a penetration rate of about 40%. If it were to achieve that level of penetration in the rest of the world -- even excluding China -- paid subscribers could grow more than 2.5 times from its current level of 94 million to 240 million worldwide. This excludes potential market increases from population gains and further broadband penetration.

Economies of scale at play

Let's not forget decreasing incremental costs, which is the cost of adding each additional subscriber. Once Netflix has built out its library of streaming content, a greater portion of the revenue from each additional subscriber will drop to the bottom line. Netflix has been hard at work growing its portfolio of self-produced original programs. It plans to spend $6 billion in 2017 up from $5 billion in 2016. In its most recent shareholder letter, it stated "it is clear to us that high quality content travels well across borders." The ability to spread the cost of its content across an ever-growing base of global customers produces economies of scale not available to traditional linear TV broadcasters.

Amazing original content

Netflix plans to have its self-produced originals eventually account for half of the platform's content. At Goldman Sachs 25th Annual Communacopia Conference on September 20, 2016 CFO David Wells indicated that the company was still a couple of years away from that goal, estimating that it is one-third to halfway there. Netflix first began debuting exclusive original content in 2013 as a way to differentiate its offerings. Many of those shows have become wildly popular. New seasons of some of its earliest releases are still enthralling viewers including House of Cards and Orange is the New Black. It's partnership's with The Walt Disney Company's (NYSE:DIS) Marvel has produced such hits as Daredevil, Jessica Jones, The Punisher, and Luke Cage -- my personal favorites. Other offerings including Stranger Things and Making A Murderer have become cultural phenomenons. The caliber of these offerings has put the industry on notice that Netflix is a force to be reckoned with and bolstered the strength of the platform.

Netflix offices with logo in window.

Netflix has plans for half its library to be self-produced original content. Image source: Netflix, Inc.

It could still all go sideways

What could go wrong? Plenty. Cash burn could overwhelm the video purveyor. Even by its own estimates, it will produce negative cash flow of $2 billion in 2017, up from $1.7 billion in 2016. Additionally, competition is heating up in the space. Amazon.com (NASDAQ:AMZN) announced in December that it had expanded its competing streaming service to 200 countries. The e-commerce giant is one of the few companies with the resources to compete with Netflix on a global level. Finally, worldwide growth estimates may be too aggressive. Netflix virtuous cycle only works as it continues to add new members. If that growth stalls before the build-out is complete, it could come crashing down.

My money is where my mouth is

Even in the face of those potential challenges, my money is still on Netflix. I think Netflix has executed its plan nearly flawlessly, its Qwikster debacle notwithstanding. The worldwide expansion is on track and the company very rarely misses its own internal financial and subscriber growth estimates. That, plus the success of its original content, proves to me that Netflix is company that is connected to its customers.

So long as the results keep proving that, I don't plan on selling any time soon. 

Danny Vena owns shares of Amazon, Netflix, and Walt Disney and spends waaay too much time watching Netflix. Danny Vena has the following options: long January 2018 $80 calls on Walt Disney and short April 2017 $105 calls on Walt Disney. The Motley Fool owns shares of and recommends Amazon, Netflix, and Walt Disney. The Motley Fool has a disclosure policy.